Sökning: "high kappa number pulp"

Visar resultat 6 - 10 av 18 avhandlingar innehållade orden high kappa number pulp.

1. 6. Some factors affecting the amount of residual phase lignin during kraft pulping

   Författare :Mikael E. Lindström; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Deligniflcation; Residual phase lignin; Hydrogensulfide ion; Hydroxide ion; Polysulfides; Ionic strength; Temperature; Lignin; Kraftpulping; Selectivity; viscosity; Kappa number; chemical degradation; Disproportionation; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : The amount of lignin which needs to be removed according to the slow residual delignification phase in kraft pulping, i e residual phase lignin, has been studied as a function of the process conditions. The variebles studied were the concentrations of hydroxide ions, hydrogensulfide ions, sodium ions (ionic strength) and temperature. LÄS MER

3. 7. On the Interrelation Between Kraft Cooking Conditions and Pulp Composition

   Författare :Catrin Gustavsson; Mikael E. Lindström; Jorge Colodette; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Delignification; Kraft pulping; Residual phase lignin; Hydroxide; Hydrogen sulphide ion; Ionic strength; Temperature; Bleachability; Hexenuronic acid; Carbohydrates; Cellulose and paper engineering; Cellulosa- och pappersteknik;

   Sammanfattning : In the early 1990’s, a lot of work was focused on extending the kraft cook to a low lignin content (low kappa number). The driving force was the need to further reduce the environmental impact of the bleaching, as less delignification work would be needed there. LÄS MER

4. 8. The Impact of Dissolved Matter on Fiberline Processes

   Författare :Caroline Wilke; Ulf Germgård; Niclas Andersson; Juha Fiskari; Karlstads universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bleach plant control; Carbonate; Carryover; Chlorine dioxide bleaching; COD; Dissolved lignin; Dissolved matter; Fiberline control; Filtrate; Hexenuronic acid; Hydrogen peroxide bleaching; Kappa number; Oxygen delignification; Wash loss; Chemical Engineering; Kemiteknik;

   Sammanfattning : The impact of dissolved matter on the performance of four fiberline process stages was investigated: oxygen delignification, hot acid treatment, chlorine dioxide bleaching, and hydrogen peroxide reinforced alkaline extraction. In particular the impact on delignification due to dissolved lignin was studied. LÄS MER

5. 9. On the Process Development of an ECF Light Bleaching Sequence for the Production of High Quality Softwood Kraft Pulp and Low AOX Formation

   Författare :Sara Starrsjö; Juha Fiskari; Mikael Lindström; Olena Sevastyanova; Maria Boman; Peter Sandström; Mittuniversitetet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemical Engineering; Natural Science; Chemical Pulping; Softwood; Kraft Pulp; Bleaching; ECF light bleaching; Chlorine Dioxide; AOX formation; Delignification; Bleachability;

   Sammanfattning : The aim of this work is to contribute to the process development of the ECF light bleaching sequence Q(OP)D(PO) by providing a better understanding of the bleaching of softwood kraft pulp. There are few published studies on this type of sequence, and more knowledge is needed on how to reduce environmental impact, improve cost-effectiveness and ensure a high pulp quality. LÄS MER

7. 10. Kraft Pulp Fibre Surfaces. Chemical Composition and Effect on Pulp Bleachability

   Författare :Anette Heijnesson Hultén; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ray cells; carbohydrates; Kraft pulps; enzymes; lignin; fibre surfaces; metal ions; bleachability;

   Sammanfattning : The work presented in this thesis concerns studies of kraft fibre surfaces in respect of chemical composition and effect on pulp bleachability. Kraft fibre surfaces were studied by mechanical peeling using a disintegrator operated at 20.000-200.000 revolutions and a pulp consistency of 3% or 4. LÄS MER